seasonal epidemic

• 季节性流行

seasonal epidemic的用法和样例：

例句

1. Seasonal flu normally infects one in ten people, so far swine flu has infected a third of the people that have come into contact with the disease.
   季节性流行感冒的传染率为十分之一，但迄今为止，但凡与猪流感病毒有接触的人，三分之一都会被感染。